Differential hoisting and lowering apparatus.



L. TABULO.

DIFFERENTIAL HOISIIING AND LOWERING APPARATUS.

APPLICATION FILED DEC. WI 1912.

1 l ,39% Patented Apr. 3, 1917.

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L. TABULO. DIFFERENTIAL HOiSTlNG AND LOWERING APPARATUS.

APPLICATION FILED DEC-10.19l2.

Patented Apr. 3, 1917.

2 SHEETS-SHEET 2 LOUIS TABULO, OF LONDON, ENGLAND.

DIFFERENTIAL HOIS'I'ING AND LOWERING APPARATUS.

Specification of Letters Patent.

Patented Apr. 3, 1917.

To all whom it may concern:

Be it known that I, LOUIS TABULo, a subject of the Emperor of Austria-Hungary, residing at 22 Valmar road, Denmark Hill, London, S. E., England, have invented new and useful Improvements in Differential Hoisting and Lowering Apparatus, of which the following is a specification.

The invention relates to hoisting and lowering apparatus and consists of improvements in the invention described and illustrated in the specification of my United States Patent No. 1,014,728.

According to the invention described in the above referred to specification a differential hoisting and lowering apparatus was rendered self-sustaining by means of brakes acted on by the load and operatively con nected through the medium of a free-wheel device to the lower pulley of the apparatus.

The present invention consists of an improved brake by which the braking effect exerted by the load is arranged so as to be proportional to the gear of the apparatus, thus enabling the efl'ort required to lower the load, when the lowering pulley has to be rotated against the action of the brake, to be reduced to a minimum. The invention also comprises a particular construction of freewheel device for use with the above referred to brake.

The improved brake consists of a band, strap, rope or the like which is wound two or more timesaround a brake drum and is anchored at one of its ends to the frame supporting the brake drum'and the pulley or sheave cooperating with said drum and is connected at its other 0r free end to a lever which is pivotally connected at its inner end to said frame and is acted on by the load. The position of the point of application of the load will correspond approximately to the theoretical position necessary to obtain a true balance according to the gear of the apparatus, but will slightly vary from said theoretical position owing to the necessity of allowing for friction and providing a margin of safety. For instance if the relative diameters of the pulleys in the upper block of the differential hoisting and lowering apparatus are as 2 to 1, giving a relative velocity ratio of 4 to 1 owing to the doubling of the chain, then the braking effect exerted by the load through the medium of the lever will be approximately one-quarter of the load, that is to say the theoretical weight which would be required to produce a balance if there was no braking effect.

which bear against the outer periphery of the ring fitting said eccentrically disposed hub and against the inner curved surfaces of said segmental pieces. The free-wheel device is operatively connected to the pulley or sheave with which it cooperates by means of a pin attached to one of the segmental pieces and an arc-shaped slot formed in the pulley or sheave, or by means of a pin secured to the pulley or sheave and a slot formed in one of the segmental. pieces.

The invention is illustrated by the accompanying drawings.

In these drawings Figures 1 and 2 are an elevation and a vertical section illustrating the improved free-wheel device. Fig. 3 is an elevation of the pocketed pulley used in COIlJllIlCtlOIl therewith. Figs. 4 and 5 are front and side elevations illustrating the application of the present improvements.

Figs. 6 and 7 are two diagrams indicating how the point of suspension of the load from the brake lever would be varied according to the gear of the apparatus.

Referring first to the construction of the improved free-wheel device illustrated by Figs. 1 to 3, 1 is a pocketed wheel which is provided with an eccentrically disposed hub 2, and 3 is a hollow brake drum which is made of box section and is formed with a peripheral groove 4 for the reception of a brake strap, hereinafter referred to. 5 is a ring fitting loosely on the eccentrically disposed hub 2 of the pocketed wheel 1. 6 are segmental pieces resting against one another and adapted to bear against a surface provided in the interior of the brake drum 3, and 7 are rollers bearing on the loose ring 5 and against the inner surfaces of the seg- 'I mental pieces 6.' Sis a studsecured to one of the segmental pieces 6 and projecting into a slot 9 formed in the pocketed wheel 1.

, The above described free-wheel device acts as soon as the chain is released the load acting on the pocketed pulley 1 will cause one or more of the segmental pieces 6 to be immediately forced into contact withthe inner surface of the brake drum 3, thus preventing running down of the load. l/Vhen, on the contrary, the pocketed pulley 1 is turned through a small angle in the opposite direc- ,ti'on, that is to say in the lowering direction,

the oneor more segmental pieces 6' then in i contact with the inner surface of the brake 2 5 drum 3, as a result of the downward pull of the load, will lock the pocketed pulley l'to the brake drum 3 and the two will turn as one piece, the brake, drum 3 then rotating inopposition to the resistance oifered by the brake strap bearing against said brake 'drunn-a resistance. which will not be proportional to the whole load but only to a portion thereof, which will depend on the mechanical advantage of the gear, plus a small allowance.

The ring of rollers 7 interposed between theeccentrically disposed hub 2 of the pock- {tion as the rollers 7 prevent any possibility eted pulley 1 and the segmental pieces 6 is an important feature of the present invenof the parts becoming jammed, while the ring'5 fitting said hub, which from an operative point of view acts asfa part of said hub, serves the useful purpose of providing an annular, recess in which said rollers 7 can be read ly placed 111 j position against the inner surfaces of the segmental pieces 6' and by which displacement or disturbance of the pocketed-pulley 1 is. placed in position,

of a strap'lO, which iswound'more than once 'around'the brake drum 3, as shown "in dotted lines in 'Fig. 2, and is attached at one of "its endsfto a fixed point and at its other end l-toe pivoted lever which is acted on by the rollers 7 is prevented when the hub of the which wot d inevitably occur if nosuch ring were used The ring-5 could however be dispensed with.

, The-above described free-wheel dev ce is usedin conjunction with'a brake consisting :lo'ads ring l lwliich is divided so that it may be readily sprung into position or other like .devicefis interposed between the'brake strap 10 and thebrake drum 3' for the pur- .pose 'of preventing wear: of the brake strap.

In cases when the apparatus is provided with quick running gear it is advisable to make the hook by which the load is suspended of considerable weight so that the brake band may at all times remain in frictional'eontact with the periphery of the brake drum, thereby not only preventing running down, when no load is suspended, but insuring that the lower pulley block shall hang plumb. The same result may be effected by suitably. weighing the lever. It is to be understood that in all cases, the divided ring or other parts interposed between the brake strap or the like, and the brake drum, would be prevented by any suitable means from rotating with said drum.

The action of this brake as well as its cooperation with the improved free-wheel device will be understood from the following description of Figs. 4. and 5.

In these figures, 12 and 13 are the upper and lower blocks of a differential hoisting and lowering apparatus, and 14- is the endless chain thereof. 15 and 16 are the differential pulleys, shown as being formed in one though they could be operatively connected to one another by means of a freewheel device, as described in the complete specification of my British Letters Patent No. 15,0a0 of 1909, when it is desired that there shall be several speeds for hoisting. The lower block 13 is fitted with a pocketed pulley 1 which is operatively connected to a brake drum 3 by means of a free-wheel device consisting of the arrangement of segmental pieces, ring of rollers, stud and coaeting slot described with reference to Figs. 1 to 3. The brake strap 10, which would be used in conjunction with an interposed divided ring or the like, is connected at one of 7 its ends to the frame 17 of the block 13, and

is connected at its other end to the outer end of a lever 18 which is pivoted at its innor end to said frame 17. The hook 19 for carrying the load is suspended from the lever 18 at a point intermediate between the ends of the lever. The exact position of said point of suspension will correspond approximately to the theoretical position necessary to obtain with the particular gear used a true balance, but will, as already mentioned, slightly vary from said theoretical position owing to the necessity of allowing for friction and providing for a margin of safety. tive diameters of the upper pulleys 15 and 16 ofthe apparatus are 2 to 1, as shown in Fig; 6,'then the load hook 19 should be suspended from the lever 18 at a point which should theoretically be exactly midway between'the point at which the lever 18 is pivoted to. the frame 17 and the point at which the brake strap 10 is connected to the lever 18, but is slightly displaced to the For instance, if the relaright of said theoretical position so as to allow for friction and to provide a certain margin of safety, as aforesaid. Similarly, if the relative diameters of the upper pulleys 15 and 16 of the apparatus are as 3 to 2, as shown in Fig. 7 then the load hook 19 should be suspended from the lever 18 at a point corresponding toone-third of the distance obtaining between the point at which the lever 18 is pivoted to the frame 17 and the point at which the brake strap 10 is connected to the lever 18, but for the reasons already given with regard to the preceding instance, Fig. 6, the point of suspension of the load hook is slightly displaced to the right of the theoretical position.

Having now described my invention what I have invented and desire to secure by Letters Patent of the United States is as follows 1. A self-sustaining lower pulley block for difierential hoisting and lowering apparatus comprising a pulley rotatably mounted within the frame of the block and formed with peripheral surfaces adapted to be gripped by the chain of the apparatus, a brake drum mounted by the side of said pulley, a free-wheel device operatively connecting said brake drum and pulley, a lever pivoted at its inner end to said frame, a brake band which is wound more than once around said brake drum anchored at one of its ends to said frame and connected at its other end to the outer end of said lever, and a load hook suspended from said lever at a point which is intermediate between the point at which said lever is pivoted to said frame and the point at which said brake band is connected to said lever and which corresponds to the difference between the diameters of the upper pulleys of the apparatus, substantially as described.

2. A self-sustaining lower pulley block for differential hoisting and lowering apparatus consisting of the combination of a pulley rotatably. mounted within the frame of the block and formed with peripheral surfaces adapted to be gripped by the chain of the apparatus and with an eccentric boss, a brake. drum of box section mounted by the side of said pulley, a free-wheel device operatively connecting'said brake drum and pulley and comprising a ring of rollers bearing against the eccentric boss of said pulley and segmental pieces interposed between said rollers and the walls of said hollow brake drum and connected to said pulley by means of a slot in said pulley and a pin carried by one of the segmental pieces, a lever pivoted at its inner end to said frame, a brake band which is wound more than once around said brake drum anchored at one of its ends to said frame and connected at its other end to the outer end of said lever, and a load hook suspended from said lever at a point which is intermediate between the point at which said lever is pivoted to said frame and the point at which said brake band is connected to said lever and which corresponds to the difference between the diameters of the upper pulleys of the apparatus, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

LOUIS TABULO.

Witnesses:

ARTHUR F. ENNIS, O. J. WORTH.

topics of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

